From: James Edward Gray II <james@...>
Date: 2006-04-17T08:11:38+09:00
Subject: Re: Simple Enumerations in Rub

On Apr 16, 2006, at 2:55 PM, Rusty Geldmacher wrote:

> http://www.soapboxsoftware.org/articles/2006/04/15/a-simple- 
> enumeration-pattern-for-ruby
>
> I would greatly appreciate feedback from the Ruby community!

Quoted from the article:

"That in itself is not a very challenging or interesting problem. We  
can certainly create a class with a list of constants, such as in the  
example below.

class Direction
   North = 0
   East = 1
   West = 2
   South = 3
end

Though simple, this solution does not satisfy our design goals. For  
one, it makes it nearly impossible to reverse map values. With that  
class above, how would I determine that the number 2 corresponds to  
the value �West�?"

Reflection:

 >> class Direction
 >>   North = 0
 >>   East = 1
 >>   West = 2
 >>   South = 3
 >> end
=> 3
 >> Direction.constants.find { |c| Direction.const_get(c) == 2 }
=> "West"

"Another goal it does not satisfy is the ability to iterate through  
the members of the enumeration."

 >> Direction.constants.each { |c| puts "#{c} = #{Direction.const_get 
(c)}" }
South = 3
West = 2
East = 1
North = 0
=> ["South", "West", "East", "North"]

Both of those are just FYI.  I did enjoy reading the article.  :)

James Edward Gray II